this is a great news to view this running on wordpress. i'm freaking out! By the way, use of roles of users is a strong limitation.

Think having 10 users that work together, everyone can create own tasks, few of these (Admins) can create task to others. Roles is the best way to do this.

But if users work on different projects, few in one, few in others and few in same projects.
I cannot see a way to connect users to a project directly but just using roles, this mean that all editor people (or custom roles) view the same projects also if these are not theirs.

I can create more custom roles to manage this, but 1 user cannot belongs to multiple roles.

It should be useful to manage groups of users instead of roles, it's more "handy", and bypass this great wp limitation.